Attachment plug



|-|`. cl. KARsT ATTACHMENT PLUG Nov. I8, ,1938;

FiledNOv. 13, 1955 Holwgofifdr y ftake up au `ofi th-sleek in fr*.UNITE-eures socket.' It 1s thus 1o Patented Nov. 8,`

PATENT omer.

*y Howard C. Karst, Hanover, Pa., `ausignor to Belden Manufacturing Company, Chicago,y lll., ay

corporationot Illinois d appunti@ Number-i3, 1.935,-sem1n0. 49,599

" scisma, 01. 113-361) e L l invention relates to electric 'attachment IIn the use of numerous electrical appliances,

such as portameferiuajetc., 1t frequently Joccurs e that an appliance is used at such a point as to y d l d the'attachment cord, thus Ytransmitting a slight pull to the attachment plug which results in pulling the plug from the necessary for the operator to stop work andreplace the plug. Moreover,con` ventional plugs and sockets vbecome loose with respect to each 'otherand it frequently occurs that an erttremely s light",movement of the at-` tachment cord -will"`detach the plug from the socket. `I am aware that prior devices have been developedI4 with the idea `of overcoming the difficulties referred to,` but such prlorjdevices involve disadvantages such as'the use of afmultiplicity l. oi parts resulting d in substantial production costs and the liability o'f mechanical derangenient,`

An important object of the present invention is to provide an extremely simple type of plug and socketconnection wherein the parts are automatically locked infengagexnent with each other and wherein the parts maybe readily disengaged whendesired. v r d A further object is [to provide a-'device of the characterreferredto` lwherein the prongs of the plug varefrnovable inwardly to release them from the socketelements, and wherein the movement of the prongs is `accornplishedfby exertingnan inward pressureonvthe body'of the plug.` v

Avr further Objectis to provide an attachment metallic fasteningelements and which may ,be

` quickly and completely assembled without the use of tools. d d d l 4A further object isv to provide novel means in .a device of the charactery referred to for normally urging the plug prongs outwardly 'to their normal relative positions.

A further object is toprovide means of the `character just referredvto which includes porftions insertablebetween the ends of the cable wires to insure against short circuiting across such wires.

A further object is to provide a novel plug and l socket combination of thegeneralcharacter red will become apparent during the course of the following description f I own one embodiment r `ferred to wherein the socket is capable of use with conventional attachment plugs.

Other objects and advantages ofthe invention In the drawing Ihave s oi the invention. :Inthis showing: r

Figure 1 isA a perspective view of the plug.,r Figure 2 is a central vertical sectional view o the same, the prongs being shown in elevation.

Figure is a similar viewoian attaching socket, r -Flgure`4 is a detail section on libel-" A o! Fig- 5 ure3,and, z

Figure 5 is al detail perspective vview of one of the prongs oi the-plug. j d

Referring to the drawingthe vnumeraly I0 designatesthe body of theplugjfand such body` is formed of an integral block of `resilient material such as rubber.v The plug is 'preferably'formed flat on opposite/sides as at Il and has its" edge portions tapered'to increasein width towardy the prong end of the plug as indicated by the numeral l2." Serrated finger grip portions ISV-"are preferably provided at the wider end of the plug to facilitate inward pressure thereagainst for apurl pose to be described.

The plug is provided with a central relatively largejrecess I4 opening through the'` larger end of the plugin amanner to bedescribed; and at its smaller endthe plug is provided `with a central 'openingj I5 to receive the usual electric cable I6. r This cable is conventional and is illustrated as containing a pair of conductor wires l1 each insulated'as at I8. d 1 d r A pair of prong members I9 is adapted to be connected to the body of the plug." Each'ol.' these prong members is provided with anupper end portion 20 preferably having a pair of openings 2| therethrough for reception of the wires Il in a manner to be described. Intermediate its ends, each prong member is oiiset inwardly to provide a shoulder 22, `andthe prong per se `23` is provided with a preferably rectangulariopen# ing'uffor a purpose to be described. At opposite edges of the opening il, the plug is provided with substantially parallel recesses 25 each adapted to receive the extremity of the inner end `2070iy 40 one of the prong members. e l The prong members'are arranged'in theplug body in' the manner shown in Figure 1, the open; ing Il being providedfwith shouldersY 26 engageable with the shoulders 22 ofthe prong members. 45 A resilient plug 21' is inserted in the wider end ofthe plug body in "the'mariner shown in Fig'-4 ure 2. This plug is provided with extended portions` 28 overhanging the shoulder portions of the prongs vto retain` them inposition against the shoulders 26. Between the shoulders 26 of l the-adjacent end of the bodyrthe plug 21 engages the` prong membersto exert lan outward force thereagainst andthus retain the prong members in their proper relative positions aswell asrto reously stated, the plug 21 is resilient, being preferably formed of rubber, and is insertable from the wider end of the plug by exerting endwise pressure thereagainst. 'I'he inner end of the plug 21 is provided with an extending tongue portion 29 which extends between the insulated portions I8 of the conducting wires, as shown in' Figure 2.

A socket suitable for use with the plug is shown in Figures 3 and 4. This socket is shown as being of the threaded type adapted for reception in threaded sockets, but it will become apparent that this type of socket is shown merely for the purpose of illustration `and the socket may be of the usual wall outlet type. The socket comprises a body 30 of generally conventional size and shape having recesses or openings 3l therein to receive the prongs 23. Contact members 32 and 33 are arranged in the socket and each is provided with a perfectly rectangular tongue 34 stamped therefrom for reception in one of the prong openings 24.v I'he tongues 34 accordingly extend partially across the prong openings 3|, and the upper ends of the socket contacts' are turned outwardly as at 35 to be embedded inl the material of the socket body' 3|) and thus act as guides for the tongues 23. "I'he contact 32 is elec-l trically connected to the threaded shell 36 of the socket, while .thecontact 33 is electrically connected to the usual base. contact 31.

The operation of the device is as follows:

In assembling the elements in the plug, the end of the cable I6 is i'lrst inserted through the opening I5 and pushed from the opposite end of the plug. The end of each wire |1 is then inserted -through one of the openings 2| from the inner face of the prong member and then through the other opening 2|, in the manner shown in Figure 2. The prong members are then inserted into the plug body with the extremities of the prong members inserted in the recesses 25. The plug 21 is then inserted into the end of the plugbody and pressure is exerted thereagainst to force the plug into position. Both the plug 21 andthe plug body l0v are formed of resilient rubber and the inward forcing of the plug 21 deforms this element inwardly to some extent while expanding the larger end of the plug body I0, thus facilitating the placing of the plug 21 in position.

With the parts assembled in the manner described. vthe upper ends of the prong members are prevented -from swinging inwardly by engagement in the recesses 25. Theplug 21 resiliently urges the prong members outwardly, thus effectively seating the shoulders 22 on the shoulders 26, thus preventing the prongs from being pulled outwardly from the' plug body. Moreover, the extending tongue 29 extends between the insulated portions of the free ends of the wires |1 thus effectively preventing the short circuiting of the wires no matter how roughly the device may be handled. The plug body H) exerts an inward pressure against the portions of the wires |1 arranged outwardly .of the prongs thus maintaining the wires in effective electrical engagement with the prongs without the use of the usual ventional connecting cables I3.

l 2,136,103 tain them in position in the p1ug body. As previof the size of the wires employed in the con- The rubber body I0 is readily deformable to accommodate the portions of the wires referred to.

In the use of the device it merely is necessary to insert the prongs 23 in the openings 3| of the sockets, and when the parts reach the proper position with respect to each other thetongues 34 snap into the openings 24 of the prong members to eectively lock the elements together. Accordingly, the appliance connected to the cable I6 may be used in any position within the length of the cable IB and slight pulls on this cable will not cause the plug to be pulled from the socket as is true in conventional constructions. When it is desired to release the plug from the socket it merely is necessary to exert an inward pressure against the serrated fac |3, the thumb and forenger of one hand being conveniently used for this purpose. The operation referred to presses the extended ends of the prong members relatively inwardly, assuggested in dotted lines in Figure 2, thus releasing the openings 24 from the tongues 34,- whereupon the plugl may be pulled from the socket.

In conventional plug constructions the prongV the socket illustrated and the tongues 34 will notengage in the small openings in the con,- ventional prongs. l'I'hus the socket may be employed with conventional plugs, but it is particularly intended'for use in connection with the plug illustrated.

From the foregoing it will be apparent that the present device is extremely simple in construction and `embodies the use of a minimum number of parts which may be cheaply manufactured vancl readily assembled. No metallic fastening elements such as screws, bolts or rivets are employed, and the assembly of the elements of the plug is accomplished without the use of tools. The parts will remain effectively interiocked against accidental displacement, but the plug may be easily removed when desired. While the socket has been illustrated as being of the screw type, it will be obvious that lt may be of any type such -as a conventional wall outlet socket, as previously stated.

If it becomes necessary to open the plug for any reason, the holding plug 21 may be removed by the use of a screw driver. Such implement may be alternately applied at opposite sides of the plug 21 and the latter pried out of position, whereupon the prongs may be withdrawn from the plug body. y

It is to be understood that the form o! the invention herewith shown and described is to be taken asa preferred example of the same and that various changes in the shape, size and arrangement of parts'may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. A soft rubber electric connector plug comprising a main body member having its front end provided with an opening for receiving a pair of contact prongs, and an auxiliary body member intermediate said prongs, said main body ders on opposite sides engaging the inner side of the offset portion of each'of said prongs, whereby said auxiliary body element is locked to said plug body against vendwise displacement i therefrom, through the agency of said contactv prongs.,

2. An electric plug connector comprising a main body member, an elongated auxiliary body member, Vand a pair of contact prongs, said prongs and auxiliary body ymember being seated in a socket in said main body member with the prongs projecting forwardly from the front end of the main body member, said auxiliary body `member being disposed intermediate the portions of said prongs within said body member and having a transverse dimension to engage the prongs and hold them spaced and engaged with side walls of the socket, each of said prongs having an integral shoulder cooperating with.

complimentary shoulders on the main and auxiliary bodies to retain the prongs and the auxi iliary body in position, the minimum cross sectional width of said auxiliary body member being substantially equal to the width of said contact prongs, and said main body member having its cross sectional width materially less than its cross sectional length in the plane of the prongs and the auxiliary body member, the main and auxiliary body members being of soft rubber-like material whereby the bodies may be compressed `and the prongs thereby moved towards one another.

3. An electric plug connector comprising an elastically yieldable body having a base portion provided with a major'cross sectional width and a minor cross sectional width at right anges thereto, said body being provided witha socket opening through the base and having major and minor cross sectional dimensions extending in directions corresponding to the major and minor dimensions of the base of the body, spaced contact prongs in the socket and disposed in the major cross sectional dimension of the base of the body and projecting outwardly through the entrance opening thereof and lying against walls of the socket, an elongated removable elastically yieldable auxiliary body member lying in the socket between the prongs and in contact with said prongs and holding the same spaced and in place against walls of the socket, the width oi' the auxiliary body at right angles to the plane of the prongs being substantially equal to the width of the prongs, each of said prongs having an integral shoulder cooperating with complimentary shoulders on the main and auxiliary bodies to retain the prongs and the Aauxiliary body in position. the wall portions of the body at the ends ofthe major dimension of the socket against which the prongs are held having thick ness and bulk sufficient to hold the prongs without tearing, and the wall portions of the socket extending along rthe major cross sectional dimension of the socket being thin enough' to permit of the socketed portion of the body being compressed by hand and the prongs thereby drawn towards one another.

' HOWARD C. KARST. 

